nigelspeedy
Well Known Member
Recently I finished up a pretty thorough experiment where I varied the ignition advance settings of my PMag using an EICommander. To date I have made 100 changes with the engine running in flight. My engine is a fuel injected parallel valve Lycoming. The dual PMags and EICommander are wired as per their respective instructions.
The purpose of this thread is to pass on my experiences with the combined PMag and EICommander system as it relates to making changes with the engine running. This thread is not about what the right advance value under any given situation may be, or why you may want to experiment with it.
1. When you send a new timing settings from the EICommander to the PMags plug firing is suspended briefly while the new map is being written. This will feel like you took the ignition key and went Both-Left-Both-Right-Both. i.e. a quick inflight mag check. Not really disturbing once you know to expect it. Probably lasts about 2 seconds in total and is normal.
2. It takes a quite a few button pushes to adjust an ignition settings map in the EICommander, save it, then send it to the PMags. A result of deep menu structure and limited display space and buttons. It takes quite a bit of ground practice to be able to do this without error airborne. If you only have a couple of settings that you want to experiment with you can save up to 5 timing maps and have them prepared on the ground which will cut down the button pushing but limits the range of values you can experiment with.
3. The minimum change you can make to timing is in steps of 1.4 degrees. This is the result of 360 degrees / 256 bits. You may think this is pretty coarse but my results indicate that it takes about twice that to see any discernible change in the aircraft and engine so don't fret.
4. When you put in maximum timing value what you see on the display will be that value + 1.4 degrees. So lets say you think the maximum timing value you ever want your engine to see is 25 degrees, you program that via the EICommander. In flight when RPM and MAP allow you will actually see up to 26.4 degrees. So simple work around is to take what you want the maximum to be and program the maximum advance value less 1.4 degrees.
5. When you make an adjustment to the Shift parameter it also affects the maximum amount of advance you see. So lets say the maximum advance value you have set is 36 degrees but you want to delay the increase in advance due to reducing MAP i.e. reduce the advance at higher power/MAP. So you put in a -1.4 deg shift. This will delay the onset of additional advance but you will now only be able to get 34.6 degrees of advance (i.e. 36 deg - 1.4 deg) regardless of the MAP or RPM. So what you take or add to the timing map via the Shift function you also take or add from the maximum available. Not a fault just a limitation of the system.
6. Approximately 1 in 20 times I have experienced a fault after sending a new ignition setting. I cant say where the root cause of the problem lies but the symptoms are as follows. After you press the send button the engine begins to run very roughly and lose power. Like a very LOP mag check. Unlike the brief firing suspension that is normal this roughness does not go away. On the EICommander one of the PMags will constantly display the correct new timing value you have just sent (this is normal). The other PMag display will vary between the new value and 19.6 deg about every 5 seconds (this is not normal). The CHT will rise at a rate of about 20F per minute and the engine oil temperature will do the same. I have found two ways of fixing this fault. First, you can reload a new ignition setting, (just repeating the one you just sent has worked for me) but this takes a few button pushes and about 30 seconds all the while you will be distracted by your engine which feels like it is under great duress. Second, you can take the P Lead for the misbehaving ignition and turn it off then back on. This is quicker but be very careful to properly identify the correct ignition. I normally associate top with 1 or left and bottom with 2 or right. On the EICommander display the upper timing advance number is associated with the right ignition. It is labeled as such but the display is quite small and you could easily make a mistake in haste. Although the faulty ignition 'display' is alternating between the correct value and 19.6 deg I don't think this is when the ignition is actually firing as the level of roughness and CHT rise are counter to this. After seeing this fault I checked the PMag timing and they were both at TDC so I don't think timing was lost, as the odds of it being subsequently found perfectly are pretty low. I also sent the PMags back for an overhaul and they were both within spec. They have always run the latest firmware version. I have seen the error on both the left and right ignition, not simultaneously though. My EICommander was also returned and it had one of the comm boards replaced but I have seen this fault a couple of times since. I have never experienced this fault except immediately after sending a change. I never had this fault with just the PMags before I installed the EICommander. I have never used the PMag proprietary software to make changes to the settings.
In summary if you have dual PMags and an EICommander and you make changes to the timing with the engine running you run a small risk of seeing a fault which I think has a potential safety impact. It could be limited to the shoddy workmanship in my individual aircraft but it may affect others. Just because you did it once and didn't see the fault doesn't mean you wont see it in the future. As I say I only saw it 1 in 20 times and could not figure out what was different between the times it worked normally and the odd time that it would fault. As stated earlier I have no data that would support an opinion of the cause of the fault.
Yes I have a video showing the alternating timing on the EICommander display, but it was taken with my cell phone and I was unhappy at the time so the quality is pretty lousy. I did pass this video on to the folks at EICommander.
Be safe out there.
Cheers
Nige
The purpose of this thread is to pass on my experiences with the combined PMag and EICommander system as it relates to making changes with the engine running. This thread is not about what the right advance value under any given situation may be, or why you may want to experiment with it.
1. When you send a new timing settings from the EICommander to the PMags plug firing is suspended briefly while the new map is being written. This will feel like you took the ignition key and went Both-Left-Both-Right-Both. i.e. a quick inflight mag check. Not really disturbing once you know to expect it. Probably lasts about 2 seconds in total and is normal.
2. It takes a quite a few button pushes to adjust an ignition settings map in the EICommander, save it, then send it to the PMags. A result of deep menu structure and limited display space and buttons. It takes quite a bit of ground practice to be able to do this without error airborne. If you only have a couple of settings that you want to experiment with you can save up to 5 timing maps and have them prepared on the ground which will cut down the button pushing but limits the range of values you can experiment with.
3. The minimum change you can make to timing is in steps of 1.4 degrees. This is the result of 360 degrees / 256 bits. You may think this is pretty coarse but my results indicate that it takes about twice that to see any discernible change in the aircraft and engine so don't fret.
4. When you put in maximum timing value what you see on the display will be that value + 1.4 degrees. So lets say you think the maximum timing value you ever want your engine to see is 25 degrees, you program that via the EICommander. In flight when RPM and MAP allow you will actually see up to 26.4 degrees. So simple work around is to take what you want the maximum to be and program the maximum advance value less 1.4 degrees.
5. When you make an adjustment to the Shift parameter it also affects the maximum amount of advance you see. So lets say the maximum advance value you have set is 36 degrees but you want to delay the increase in advance due to reducing MAP i.e. reduce the advance at higher power/MAP. So you put in a -1.4 deg shift. This will delay the onset of additional advance but you will now only be able to get 34.6 degrees of advance (i.e. 36 deg - 1.4 deg) regardless of the MAP or RPM. So what you take or add to the timing map via the Shift function you also take or add from the maximum available. Not a fault just a limitation of the system.
6. Approximately 1 in 20 times I have experienced a fault after sending a new ignition setting. I cant say where the root cause of the problem lies but the symptoms are as follows. After you press the send button the engine begins to run very roughly and lose power. Like a very LOP mag check. Unlike the brief firing suspension that is normal this roughness does not go away. On the EICommander one of the PMags will constantly display the correct new timing value you have just sent (this is normal). The other PMag display will vary between the new value and 19.6 deg about every 5 seconds (this is not normal). The CHT will rise at a rate of about 20F per minute and the engine oil temperature will do the same. I have found two ways of fixing this fault. First, you can reload a new ignition setting, (just repeating the one you just sent has worked for me) but this takes a few button pushes and about 30 seconds all the while you will be distracted by your engine which feels like it is under great duress. Second, you can take the P Lead for the misbehaving ignition and turn it off then back on. This is quicker but be very careful to properly identify the correct ignition. I normally associate top with 1 or left and bottom with 2 or right. On the EICommander display the upper timing advance number is associated with the right ignition. It is labeled as such but the display is quite small and you could easily make a mistake in haste. Although the faulty ignition 'display' is alternating between the correct value and 19.6 deg I don't think this is when the ignition is actually firing as the level of roughness and CHT rise are counter to this. After seeing this fault I checked the PMag timing and they were both at TDC so I don't think timing was lost, as the odds of it being subsequently found perfectly are pretty low. I also sent the PMags back for an overhaul and they were both within spec. They have always run the latest firmware version. I have seen the error on both the left and right ignition, not simultaneously though. My EICommander was also returned and it had one of the comm boards replaced but I have seen this fault a couple of times since. I have never experienced this fault except immediately after sending a change. I never had this fault with just the PMags before I installed the EICommander. I have never used the PMag proprietary software to make changes to the settings.
In summary if you have dual PMags and an EICommander and you make changes to the timing with the engine running you run a small risk of seeing a fault which I think has a potential safety impact. It could be limited to the shoddy workmanship in my individual aircraft but it may affect others. Just because you did it once and didn't see the fault doesn't mean you wont see it in the future. As I say I only saw it 1 in 20 times and could not figure out what was different between the times it worked normally and the odd time that it would fault. As stated earlier I have no data that would support an opinion of the cause of the fault.
Yes I have a video showing the alternating timing on the EICommander display, but it was taken with my cell phone and I was unhappy at the time so the quality is pretty lousy. I did pass this video on to the folks at EICommander.
Be safe out there.
Cheers
Nige
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